fix(widget): 배너 가상 목록 갱신을 안정화한다

app/src/main/java/kr/co/vividnext/sodalive/v2/widget/banner/BannerAdapter.kt

@@ -1,5 +1,6 @@
 package kr.co.vividnext.sodalive.v2.widget.banner
 
+import android.annotation.SuppressLint
 import android.graphics.Outline
 import android.view.LayoutInflater
 import android.view.View
@@ -38,19 +39,17 @@ class BannerAdapter(
         this.items.addAll(items)
         val newItemCount = itemCount
         when {
-            previousItemCount == 0 && newItemCount > 0 -> notifyItemRangeInserted(0, newItemCount)
+            previousItemCount == 0 && newItemCount == 1 -> notifyItemInserted(0)
-            previousItemCount > 0 && newItemCount == 0 -> notifyItemRangeRemoved(0, previousItemCount)
+            previousItemCount == 1 && newItemCount == 0 -> notifyItemRemoved(0)
-            previousItemCount == newItemCount -> notifyItemRangeChanged(0, newItemCount)
+            previousItemCount == 1 && newItemCount == 1 -> notifyItemChanged(0)
-            else -> {
+            else -> notifyVirtualItemsChanged()
-                notifyItemRangeRemoved(0, previousItemCount)
-                notifyItemRangeInserted(0, newItemCount)
-            }
         }
     }
 
     fun setItemSizePx(itemSizePx: Int) {
+        val shouldNotify = this.itemSizePx != itemSizePx
         this.itemSizePx = itemSizePx
-        notifyItemsChanged()
+        if (shouldNotify) notifyVisibleItemsChanged()
     }
 
     fun setOnClickItem(listener: ((BannerItem) -> Unit)?) {
@@ -62,8 +61,9 @@ class BannerAdapter(
     }
 
     fun setPreviewImageResource(resId: Int) {
+        val shouldNotify = previewImageResId != resId
         previewImageResId = resId
-        notifyItemsChanged()
+        if (shouldNotify) notifyVisibleItemsChanged()
     }
 
     fun toRealIndex(position: Int): Int = if (items.isEmpty()) 0 else position % items.size
@@ -106,9 +106,17 @@ class BannerAdapter(
         }
     }
 
-    private fun notifyItemsChanged() {
+    private fun notifyVisibleItemsChanged() {
-        val count = itemCount
+        when (itemCount) {
-        if (count > 0) notifyItemRangeChanged(0, count)
+            0 -> Unit
+            1 -> notifyItemChanged(0)
+            else -> notifyVirtualItemsChanged()
+        }
+    }
+
+    @SuppressLint("NotifyDataSetChanged")
+    private fun notifyVirtualItemsChanged() {
+        notifyDataSetChanged()
     }
 
     private companion object {

app/src/main/java/kr/co/vividnext/sodalive/v2/widget/banner/BannerItem.kt

@@ -1,6 +1,11 @@
 package kr.co.vividnext.sodalive.v2.widget.banner
 
+import kr.co.vividnext.sodalive.settings.event.EventItem
+
 data class BannerItem(
-    val bannerId: String?,
+    val imageUrl: String,
-    val imageUrl: String
+    val eventItem: EventItem?,
+    val creatorId: Long?,
+    val seriesId: Long?,
+    val link: String?
 )

app/src/main/java/kr/co/vividnext/sodalive/v2/widget/banner/BannerView.kt

@@ -146,7 +146,13 @@ class BannerView @JvmOverloads constructor(
             if (previewImageResId != 0) adapter.setPreviewImageResource(previewImageResId)
             if (previewItemCount > 0) {
                 items = List(previewItemCount) { index ->
-                    BannerItem(bannerId = "preview-$index", imageUrl = "")
+                    BannerItem(
+                        imageUrl = "",
+                        eventItem = null,
+                        creatorId = null,
+                        seriesId = null,
+                        link = "preview-$index"
+                    )
                 }
                 currentIndex = BannerState.from(previewItemCount, previewCurrentIndex).currentIndex
                 visibility = VISIBLE

app/src/test/java/kr/co/vividnext/sodalive/v2/widget/banner/BannerViewTest.kt

@@ -67,6 +67,74 @@ class BannerViewTest {
         assertEquals(items[1], clickedItem)
     }
 
+    @Test
+    fun `adapter는 carousel 설정 시 max range notify를 호출하지 않는다`() {
+        val adapter = BannerAdapter()
+        var insertedItemCount = 0
+        var changedItemCount = 0
+        var dataSetChangedCount = 0
+        adapter.registerAdapterDataObserver(
+            object : RecyclerView.AdapterDataObserver() {
+                override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {
+                    insertedItemCount = itemCount
+                }
+
+                override fun onItemRangeChanged(positionStart: Int, itemCount: Int) {
+                    changedItemCount = itemCount
+                }
+
+                override fun onChanged() {
+                    dataSetChangedCount += 1
+                }
+            }
+        )
+
+        adapter.submitItems(listOf(sampleItem("1"), sampleItem("2")))
+        adapter.setItemSizePx(100)
+
+        assertEquals(0, insertedItemCount)
+        assertEquals(0, changedItemCount)
+        assertEquals(2, dataSetChangedCount)
+    }
+
+    @Test
+    fun `adapter는 단일 배너 설정 시 specific notify를 호출한다`() {
+        val adapter = BannerAdapter()
+        var insertedItemCount = 0
+        var changedItemCount = 0
+        var removedItemCount = 0
+        var dataSetChangedCount = 0
+        adapter.registerAdapterDataObserver(
+            object : RecyclerView.AdapterDataObserver() {
+                override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {
+                    insertedItemCount += itemCount
+                }
+
+                override fun onItemRangeChanged(positionStart: Int, itemCount: Int) {
+                    changedItemCount += itemCount
+                }
+
+                override fun onItemRangeRemoved(positionStart: Int, itemCount: Int) {
+                    removedItemCount += itemCount
+                }
+
+                override fun onChanged() {
+                    dataSetChangedCount += 1
+                }
+            }
+        )
+
+        adapter.submitItems(listOf(sampleItem("1")))
+        adapter.setItemSizePx(100)
+        adapter.submitItems(listOf(sampleItem("2")))
+        adapter.submitItems(emptyList())
+
+        assertEquals(1, insertedItemCount)
+        assertEquals(2, changedItemCount)
+        assertEquals(1, removedItemCount)
+        assertEquals(0, dataSetChangedCount)
+    }
+
     @Test
     fun `배너 view는 빈 목록이면 숨기고 단일 목록이면 counter를 숨긴다`() {
         val view = inflateBannerView()
@@ -533,8 +601,11 @@ class BannerViewTest {
     }
 
     private fun sampleItem(id: String) = BannerItem(
-        bannerId = id,
+        imageUrl = "https://example.com/banner-$id.png",
-        imageUrl = "https://example.com/banner-$id.png"
+        eventItem = null,
+        creatorId = id.toLongOrNull(),
+        seriesId = null,
+        link = "https://example.com/banner-$id"
     )
 
     private fun exactly(size: Int): Int = MeasureSpec.makeMeasureSpec(size, MeasureSpec.EXACTLY)